The ornamental design for a greasegun, as shown and described.
FIG. 1 is a front perspective view of a grease gun in accordance with our new design;
FIG. 2 is a rear perspective view of the grease gun in accordance with our new design;
FIG. 3 is a front elevational view of the grease gun in accordance with our new design;
FIG. 4 is a rear elevational view of the grease gun in accordance with our new design;
FIG. 5 is a top plan view of the grease gun in accordance with our new design;
FIG. 6 is a bottom plan view of the grease gun in accordance with our new design;
FIG. 7 is a right side elevational view of the grease gun in accordance with our new design;
FIG. 8 is a left side elevational view of the grease gun in accordance with our new design; and,
FIG. 9 is a front perspective view of the grease gun in accordance with our new design showing when a rechargeable battery and a hose are attached to the grease gun.
The broken line showing of environment structures in the drawings forms no part of the claimed design.